Effect of gelling agents onin vitro tuberization of six potato cultivars

The gelling agent Phytagel? was compared with Difco Bacto-agar forin vitro tuberization of six potato cultivars (Jaerla, Blanka, Claustar, Kennebec, Désirée, and Baraka). On a culture medium with 6% sucrose but lacking growth regulators, tuberization was higher when Phytagel? was used rather than Difco Bacto-agar, regardless of the photoperiodic regime used. Chemical analyses of the gelling agents revealed a higher mineral content and organic impurities in Bacto-agar than in Phytagel?, which is therefore recommended for microtuber production. The same gelling agent should be used in all treatments of microtuberization experiments in order to draw meaningful physiological conclusions.